Adjustable mix feeding means for block molding machines



Aug. 24, 1954 T. K. ZEVELY 2,686,950

I ADJUSTABLE IX FEEDING MEANS FOR BLOCK MOLDING MACHINES Filed Jan. 2, 1951 4 Sheets-Sheet 1 n a a;

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1 a x 1 I w M INVENTOR Zevey ATTORNEYS Aug. 24, 1954 T. K. ZEVELY 2,686,950

ADJUSTABLE MIX FEEDING MEANS FOR BLOCK MOLDING MACHINES Filed Jan. 2. 1951 4 Sheets-Sheet 2 I -l- .4 A

El E1 El @1 i- 26 VII/1% y 55 g if jy 56 64 6.3 4 56 51 5554 IN VENTOR 720772623 lei 8Z5] A ORNEYS 4, 1954 r. K. ZEVELY 2,686,950

ADJUSTABLE MIX FEEDING MEANS FOR BLOCK MOLDING MACHINES Filed Jan. 2, 1951 4 Sheets-Sheet 3 ATTORNEYJ Aug. 24, 1954 T. K. ZEVELY 2,686,950

ADJUSTABLE MIX FEEDING MEANS FOR BLOCK MOLDING MACHINES Fi led Jan. 2, 1951 4 Sheets-Sheet 4 Mm w INV ENT OR 771012203 Z eyegy W, MM W ATTORNEYS Patented Aug. 24, 1954 ADJUSTABLE Mix FEEDING MEANS FOR BLOCK MOLDING MACHINES Thomas K. Zevely, Washington, D. 0., ass' ignor to The Washington Brick (30., Muirkirlr, corporation of Maryland McL, a

Application January 2, 1951, Serial No. 203,937

(Cl. 25-1il 3-) 12 Claims 1 This invention relates to machines for molding masonry blocks of concrete mixed with cinder, slag and similar materials, and is especially directed to means for controlling the amount of mix supplied to the mold box.

In block molding machines of the conventional type embodying a horizontally reciprocabl'e, open bottom feed pan for transferring charges of moldable material from the delivery spout of a feed hopper to an open top mold box, the bottom edge of the front end wallof the feed pan serves to level off and fix the height of the: mix in the mold box and to retain any excess in the pan as the latter moves back under thehopper after filling the mold box. The topedge of said pan wall also usually carries a flexible wiper element which rubs across and cleans the bottom surfaces of the strip"- per heads on the rearward stroke of the feed pan.

It is necessary that the height of the mix left in the mold box when the feed pan returns to its rearward position be somewhat greater than the desired" height of the finished blocks because of the compression which takes place during the tamping or compacting portion of the block molding cycle. It is also necessary that the height of the mix be variable in order to compensate for the differences in compression which result from differences in the composition or density of the aggregate used. Consequently, the frontend wall of the feed pan in prior block molding machines has ordinarily been detachably connected to the rest of thepan by bolts or the like in such a manner that the position of its lower edge could be adjusted vertically by the insertion or removal of washers 0r shims between the bolted together portions of the end and side walls of the pan. Since any such vertical adjustment of the front end wall would vary the position of the wiper element carried thereby relative to the stripper shoes, it has also been necessary to provide an adjustable connection between the wiper element and the pan wall and to reposition the wiper after each adjustment of the wall.

This prior construction for varying the height of the mix in the mold box has several disadvantages. In the first place, it is necessary to stop the entire machine in order to make the desired adjustments of the front end wall of the feedpan and the wiper element, with a consequent loss in production. Secondly, the operations of unbolting and rebolting the parts, inserting and removing washers, and repositioning the wiper element require the expenditure of considerable time and labor which also increases operating costs. The necessity for a separate adjustment ofthe wiper 2 element each time the front pan wall is raised or lowered is another defect of the previously used devices. A further disadvantage resides in the fact that the washer or shim type of adjustment is of limited accuracy and cannot provide the precise control which is sometimes desired.

It is therefore the principal object of the present invention to provide a novel mechanism for readily controlling the height of the mix in the mold box of a block molding machine which will overcome the disadvantages inherent in the prior art devices intended for the same purpose.

Another objectisto providean improvedform of feed pan for block molding machines embodying a vertically movable cut-off bar for establishing the height of the mix left in the mold box which forms at least part of the front wall of the pan and is adjustable instantaneously and without interrupting the block molding cycle of the machine.

A further object is to provide a control mechanism of the character described which is electri cally actuated and capable of adjusting the posi-- tion of the cut-ed bar with a high degree of accuracy.

Still another object is-to provide a feed pan of the type above mentioned which is so constructed that the cut-off bar maybe readily adjusted without varying thepositio-n of the stripper shoe wiper element.

A still further object is-to provide a cut-off bar of the character described having removable scraper shoes of novel form which so shape the upper surface of the mix supplied to the mold box as to leave extra amounts thereof adjacent the core bars for packing therebeneath by the stripper heads.

These and other objects will appear more fully upon consideration or the detailed description of the embodiment of the invention which follows,

In this connection, it is tobe expressly understood that the specific form of mechanism described and shown in the accompanying drawings is illustrative only and is n'o'tto be construed as representing the full scope of the invention, for whicli- 3 of the stripper mechanism, the feed pan and the mold box of the machine of Fig. 1 with the mold box in section and showing the elements in the positions occupied after the mold box has been filled and during the rearward or return stroke of the feed pan;

Fig. 3 is a side elevation corresponding to Fig. 2 with certain parts shown in section and others entirely omitted in order to clearly show the structure of the improved feed pan;

Figs. 4, 5 and 6 are a plan View, a rear elevation and a side elevation, respectively, of the rear end of the feed pan showing the electric motor and associated drive by which the position of the cut-off bar may be adjusted without stopping the machine;

Fig. '7 is an axial sectional view, on an enlarged scale, of the unique sprocket arrangement forming part of the motor drive, taken substantially on line L4 in Fig. 4;

Fig. 8 is a perspective View of the front end of the feed pan with the cut-off bar partially broken away;

Fig. 9 is a vertical sectional view through the cut-off bar and wiper element of the feed pan, taken substantially on line 9-9 in Fig. 8; and

Fig. 10 is a fragmentary horizontal section, on an enlarged scale, taken substantially on line iii-iii in Fig. 9.

Referring first to Fig. l, the block molding machine illustrated therein is, except for the improved feed pan and associated elements, of a well known type for making hollow or cored blocks on plain or imperforate pallets. In this machine, the blocks 2| are formed in a mold box 22, open at both top and bottom, which is stationary except for the movements incident to vibration of the mold during the block forming operations. The moldable material or mix is supplied to the mold box through the open top thereof by a horizontally reciprocable feed pan 23, also open at top and bottom, which is moved forwardly to the position shown in Fig. l to fill the mold and rearwardly to receive the next charge of mix from the hopper 24, the feed pan being supported by rollers 25 on tracks 26 and receiving its reciprocating movement in the usual manner from the cam 2'! which is mounted on one end of a cam shaft extending transversely across the rear of the machine. During the molding operation, the open bottom of the mold box 22 is closedby an imperforate pallet 28, the pallets being fed automatically by the chains 29 from a pallet stack in the rear of the machine to a position below the mold box and then elevated into engagement with the bottom of the mold by vertically reciprocable anvil bars iii), the latter deriving their movement from a cam (not shown) mounted on the opposite end of the shaft which rotates cam 21. When the pallet engages with the bottom of the mold, the mold box is elevated slightly so that the transversely extending mold bars 31 which support the rest of the elements constituting the mold are out of contact with the portions of the machine framework on which they normally rest. The mold box is then ready to receive the charge of moldable material from the feed pan 23 which moves forwardly over the mold box to the position indicated in Fig. 1 and delivers the charge by gravity through the open bottom of the pan. During delivery of the charge, the mold box and superposed feed pan are vibrated in known manner by the motors 32 through belt drives housed in the casings 33.

When the mold has been filled, the feed pan 23 is moved rearwardly clear of the mold box so as to enable the stripper heads M, which are normally maintained in the elevated position indicated in Fig. 1, to descend into contact with the upper surface of the mix in the mold to first level and compact said mix, during which time the mold box is again vibrated and the stripper heads gradually sink by gravity as the mix is compacted, and to then move downwardly through the mold box and positively eject or strip the molded blocks therefrom as the latter are supported on the pallet 23 which is in turn resting on the anvil bars 3B. The stripper heads cease their downward movement when they reach a position such that the stripper shoes 35 on the lower ends of the heads project slightly below the bottom of the mold box, but the anvil bars 3t continue to descend until the pallet 28 and the blocks 26 supported thereon rest on the pallet chains 29. The chains 29, which are driven from the main drive shaft 36 through a transmission including the chain 3?, advance the loaded pallet to the position shown in Fig. l where the forward portion of the pallet rests on the rollers 38 of the delivery track 39, whence the pallet and blocks may be removed from the machine, either manually or automatically, and transported to the curing vault. As the loaded pallet is thus moved forwardly after the stripping operation, the chains 29 automatically bring another empty pallet into position beneath the mold box, and the anvil bars are again elevated to lift the empty pallet into engagement with the bottom of the mold. Simultaneously with the upward movement of the anvil bars, the stripper heads 34 are moved upwardly out of the mold box and returned to their initial position illustrated in Fig. l, the movement of the stripper heads being controlled by another cam (not shown) mounted on the same end of the cam shaft as the cam which raises and lowers the anvil bars.

The stripper heads 34 are rigidly connected at their upper ends to, and supported by, a horizontal plate 50 which is in turn secured to a pair of fore-and-aft bars 49 by bolts 62 and nuts 43, the bars 4| being fixed in any suitable manner, as by welding, to the lower edges of a pair of parallel beams 44 which extend from one side of the machine to the other and embrace between their ends vertical guide posts 55 which are fixed to and form part of the machine frame. Just inside the guide posts 45, the beams i4 are connected by stirrup members 36 which provide pivotal connections between the beams and a pair of links it! forming part of the cam and lever system by which the stripping mechanism is given its vertical movements in timed relation to the movements of the feed pan 23 and anvil bars 30. The upper ends of the links Al are pivotally connected to the forked ends of levers M which are fixed to a shaft (not shown) journaled in the upper portion of the machine frame, said shaft being oscillated in the usual manner by the previousl mentioned cam which controls the movements of the stripper heads. As the levers 48 oscillate, the entire stripping mechanism is lowered and raised by the beams M, the latter being guided in their vertical movement by shoes 49 which slidably engage the front and rear surfaces of guide posts 55.

In this type of block molding machine, the mold box 22 comprises side plates 59 and end plates 5| (Figs. 2 and 3) which are bolted together and to the mold supporting bars 3| to form the walls of the box, while the interior of the box is subacscpco fixed to and suspended from the lower edges of o'ore *bars 56, the latter extending across the top of the mold box and being fixed thereto in proper position by-clevises 55 in the usual manner. Surrounding the open top of thecore box 22 is a mix retaining apron having a horizontal plate 55 extending around all four sides of the box and a vertical wall -57 at the front and sides only, the rear -end of the apron being open to enable movementor the feed pan 23 over the mold box for the delivery of mix thereto.

Due to the presence of the core bars 54 and the arrangement oi the elements of the mold in such a manner as to simultaneously produce a row of "blocks having their long dimensions parand to the core bars, the stripper heads 34 are arranged in pairs, the heads of each pair being adapted to pass downwardlyonopposite sides of a core bar and to receive the core bar between them during the block compactin and stripping operations. In the usual machine of this type, the adjacentedges of each pair of stripper heads 34 and attached shoes 35 are spaced apart in permanently fixed relationship by a distance slightly greater than the Width ofthe associated core bar 54, and each stripper shoe is so shaped and dimensioned that, when inengagement with the mix in the mold box, it contact approximately half the area of the block top except for the portion immediately underlying the core bar. Ii desired, however, the conventional rigid stripper head arrangement may be replaced by the improved construction disclosed in my cop'ending application Serial No. 88,964, filed April 22., l9'49,.now-Patent No. 2,566,787, dated Septemher- 4, :1951, wherein at least some of the stripper heads are pivotally suspended from the plate 40 for limited movement about horizontal, forea'nd aft axes and means are provided for automatically producing, in timed relationship to the vertical movements of the stripping mechanism, pivotal movement of the stripper heads about their axes of suspension so as to separate each pair of shoes suflioiently to enable the core bar topa'ss therebetween and to then bring the shoes together beneath the core bar.

In block molding machines of the character.

above described as heretofore known to the art, theifront end wall of the feed pan 23, the bottom edge of which serves to level off and fix the height of the mix left in the mold box .22 as the feed pan .moves back under the hopper 24, is bolted to the pan side walls in such a manner that the position of its lower edge can be adjusted vertically only by removing the bolts and inserting or removing washers or shims between the cooperating portions of the end and side walls. In these prior machines, the front end wall of the pan also carries a flexible wiper element adapted to remove any adherent mix from the bottom surfaces of the stripper shoes 35 during the rearward movement of the feed pan, the wiper element being so connected to the upper edge of said 6 without varying the position of the stripper shoe wiper element. As shown best in Figs. 2, 3 and 8, the feed pan 23 comprises a pair-of elongated side walls 58 which extend substantially the full length of the machine in a fore and-aft direction and are permanently interconnected at their rear ends by transverselyextending plates b9 and Kit. The side walls 58 are also tied together intermediate their ends by a vertical plate 61 formin the rear Wall of the mix-holding portion of the feed pan which is open at both top and bottom, the portion of the pan rearwardly of plate iii being provided with a horizontal plate 62 adapted to close the bottom of the hopper 2 5 when the feed pan moves forwardly to deliver the *mix to the mold box 22. 'The bottom edge of vertical plate 5i slides over a stationary floor plate 53 which is supported by the machine framework in any suitable manner, as on transversely extending beams '54, beneath the discharge end of the hopper 2 3 and on the same level as the horizontal plate 56 of the apron around the top of the mold box.

In the illustratedemb'odiment of the invention, the front end wall of the feed pan is formed by a cut-off bar 65 which is movable with the side i walls 58 during horizontal reciprocation of the pan, but is so supported from said side walls as to be vertically adjustable reIative thereto even while the pan is moving. As shown in Figs. -8, 9 and it, each side wall 58 has fixed to its outer surface adjacent its forward end a guide formed of a pair or vertically extending angle irons t6 and iii welded to the side wall and upper and lower horizontal straps-t8 and 69 welded to the outer surfaces of the angleirons. Slidably housed in each of the thus formed guides is a vertically movable mounting plate it to which is fixed a laterally and forwardly projecting lug H having an inwardly turned outer end portion "12 adapted to be connected to and to support one 'endof the cut-oil? bar 65. For this purpose, each end of the cut-cit bar is recessed intermediate its upper and lower edges to providean upper arm t3 which rests on the outer end portion 12 of lug ii and is secured thereto by 'a bolt l4, and a lower arm it which enters the slot formed by the hooked extension it of the lower edge of side WE-11358. The hooked extension it is of such height as to insure engagement with the outer surface oi arm it at all vertical positions of cut-off bar 65 and thus restrain any tilting tendency of the cut-off bar as the feed pan reciprocates. The inner end portion i l of lug "ll is welded or otherwise fixed to mounting plate Hi and extends outby the angle irons "6'6 and t? and upper and lower straps 6'8 and 69 of the guide.

Simultaneous vertical movement of mounting plates it in their respective guides i produced by a novel arrangement of elements which is operable at the will of the machine operator and without interrupting the block molding cycle of the machine. As shown, the rear edge of each mounting plate "ill adjacent its upper end is re cessed as indicated at T8 to receive the rounded end it of the approximately horizontal arm of a bell crank lever 84, said lever also having an apr'oximately vertical arm '82 which extends above the upper edge of the associated side wall 53 of the feed pan. Each of hell crank levers 81 is pivotally mounted on a stud bolt 83 which passes-through a rearwardly extending ear 84 of upper strap 68 and the adjacent portion of pan side wall 158, the angle iron 66 terminating.

Referring now to Figs. 4-7, the rear end of each operating rod 85 is threaded as indicated at 98 and engages the internally threaded hub of a sprocket wheel 99 which is rotatably mounted on the rod but restrained against axial movement therealong by retention between the upper transverse plate 59 connecting the rear ends of side walls 98 and a retainer plate 99 secured to plate 99 by bolts 9! surrounded by spacer sleeves 92. The retainer p ates 99 and plate 59 thus form cages for the sprocket wheels 39 which enable the latter to rotate relatively to the threaded ends of operating rods 99 but at the same time prevent said wheels from moving axially along the rods, whereby the rods are caused to move in an axial direction when the wheels arerotated. By making the cooperating threads ofthe rod 95 and sprocket wheels 89 of a relativel small pitch, the positions of said rods, the mounting plates 79 and cut-01f bar 95 may be varied with micrometric accuracy.

In order to effect simultaneous and equal movements of the operating rods 95 and associated elements, the two sprocket wheels 89 are interconnected by a chain 93, and one of said wheels is so arranged as to be driven in either direction by a reversible electric motor 94 which is mounted on and movable with the feed pan and controlled by a suitable up and down switch 95 (Fig. 1) conveniently located at the front of the machine adjacent the main switch 96 by which the entire machine is started and stopped. As shown, the motor 94 is mounted on a platform 91 having one end pivotally connected to a standard 99 fixed to and extending upwardly from one of the side walls 58 of the feed pan and its other end supported by a jack screw 99 which is threaded into a block I99 suitably fixed to the upper transverse plate 99 interconnecting the rear ends of the pan side walls. The motor 94 is provided with a drive shaft I9I on which is fixed a sprocket wheel I92, the latter being drivably connected by a chain I93 with another sprocket wheel HM secured to and rotatable with one of the operating rod sprocket wheels 99. The pivotal mounting of motor platform 9'! on standard 9t and its support by jack screw 99 provide a readily adjustable means for removing or introducing slack in driving chain I93.

Although the sprocket wheel I94 may be permanently fixed to the wheel 99 which it is adapted to drive, it is preferable to provide a releasable, connection between the two wheels in order to avoid damage to the motor 99 in the event that axial movement of the operating rods 85 should be prevented for any reason while the motor is running. To this end, as shown in Fig. '7, the sprocket wheel 99 with which the wheel I94 is associated is provided with an elongated hub I95 on which is mounted the hub I99 of wheel I99, the two hubs being normally fixed to one another by a radially extending shear pin I9! which passes through aligned holes in the hubs and is retained in place by a snap ring I98. Should anything interfere with axial movement of the operating rods 85 at any time while the motor permit the sprocket wheel I94 to rotate freely on the elongated hub I95 of the associated wheel 89 as long as the switch 95 is actuated. The driving connection between wheels I94 and 99 may be readily renewed by simply removing the snap ring I98, extracting the broken shear pin and inserting a new one.

With this arrangement, it is evident that the position of the cut-off bar 95 may be instantaneously and accurately adjusted, even while the machine is operating and the feed pan is moving, by simply moving the control lever of switch 95 to either up or down position so as to energize and drive the motor 94 in the desired direction, whereupon rotation of motor drive shaft I 9| produces axial movement of the operating rods 85 which is in turn converted into vertical movement of the cutoff bar through the bell crank levers (BI and mounting plates I9. If desired, the mounting plate on the side of the feed pan adjacent the control switch may be provided with a suitable indicator (not shown) for informing the operator of the position of the lower edge of the cut-off bar with respect to the top of the mold box and thereby indicating the height of the mix that will be left in the box when the feed pan moves back beneath the supply hopper after filling the box. In many cases, however, it is preferable to determine the proper height of the mix by trial and error, i. e., by running the'machine with the cut-off bar at various positions and examining the finished blocks to determine which position produces the desired result. Under such circumstances, the ability of the structure of the present invention to vary the position of the cut-off bar quickly, without interrupting the block molding cycle and by as small increments as may be desired, repre sents a decided advantage and improvement over the devices heretofore known wherein any adjustment of the cut-off bar was a relatively long and laborious operation which necessitated com plete stoppage of the machine for a substantial period of time.

In order that the feed pan 23 may recipro-, cate freely in spite of the presence of the core bars 5 3 which extend upwardly above the top of the mold box, the bottom edge of cut-01f bar .65 is provided with a plurality of vertically extending slots I99 which receive the core bars as the feed pan moves back and forth over the box. The construction of the cut-off bar may be improved by providing the thus subdivided lower edge portion thereof with a plurality of removable scraper shoes I I9 which are detachably connected thereto by bolts I I I (Figs. 2, 8 and 9). The rear faces of the slot-separated sections of the cut-off bar may be recessed to receive the scraper shoes which are so dimensioned that their bottom edges extend downwardly below the bottom edge of the cut-off bar while their side edges project beyond the edges of the slot i99 so as to lie closely adjacent the vertical sides of the core bars 54. An important advantage of using scraper shoes of this character is that all wear occurs on the edges of the replaceable shoes, instead of on the edges of the cut-01f bar, thereby avoiding the necessity for replacement of the latter. As shown best in Fig. 2, the lower corners of the scraper shoes are beveled for the purpose of leaving more mix alongside each core bar than elsewhere, these extra amounts of mix being subsequently packed under the core bars by the stripper heads and thus providing more acsaeso uniformly finished an compacted blocks, particnlarly when the machine. includes the improved pivoted stripper head construction of my previously mentioned Patent No. 2,566,787. Although. it is necessary to bevel only those corners of the. scraper shoes which lie adjacent the core bars, it is. preferable to. make each shoe symmetrical with respect to a, median horizontal plane through the holes for the bolts it! so that the shoes may be inverted when wear occurs and their life thereby increased.

Instead of adjustably connecting a stripper shoe wiping element to the upper edge of the front end wall of the feed pan as. in the machines. of the prior art, the improved feed pan oi the present invention embodies a wiper element which is mounted independently of the cut-off bar and therefore does not require an adjustment of its own position each time that the-position of the cut-off bar isvaried. As shown in Figs. 8. and 9, each side wall 58. of the feed pan has: fixed to its inner face, adjacent the upper edge thereof and slightly to the rear oithe plane of the cut-off bar 65, a U-shaped saddle or seat H2 adapted to receive and support one end of a transversely extending bar H3 which forms the base of the stripper shoe wiper element and to which is fastened an upwardly extending flexible wiper blade lie of rubber or any other suitable composition. The wiper blade H4 may be detachably connected at its lower edge to the. bar H3 in any suitable manner, as by a clamping plate 1 i5 bolts i it, and is of such a height that, when the feed pan moves rearwardly after delivering the mix to the mold box, the upper edge of the blade will wipe across and clean the bottom surfaces of the stripper shoes 35. in the manner indicated in Fig. 3. As is customary in block molding machines of the character de-.

scribed, the cam which controls the vertical movements of the stripper heads is so shaped that the latteroccupy a slightly higher position during the forward stroke of the feed pan than during the return stroke so that the wiper blade will not contact the stripper shoes as the feed pan moves forwardly and brush the adherent mix off the shoes outwardly toward the front of the machine. Since the bar 1 l3 simply has a sliding fit in the supporting saddles N2, the wiper element may be easily removed whenever it is desired to replace the blade H4, but otherwise remains in a fixed vertical position which is unaffected by adjustments of the cut-off bar (it.

There is thus provided by the present inventi'on a newand improved feed pan construction 5 for block molding machines which is characteri'zed primarily by its ability to quickly vary the height of the mix left by the feed pan in the mold box at the will of the operator and Without interrupting the block molding cycle of the machine. Another feature resides in the provision of a stripper shoe wiper element which is mounted independently of the means by which the height of the mix is controlled and therefore requires no adjustment when the height of the mix is varied. The structure of the invention is relatively simple from a mechanical standpoint and is, well adapted for incorporation in machines.

already in use as well as in new installations, while the savings in labor and lost machine time resulting from its practically instantaneous, electriically actuatedadjustability will far offset the cost of the additional mechanism required in comparison with the machines of the prior art.

While.- only' one specific form. of the invention 10 has been illustrated in the accompanying drawings, it will be obvious that the inventive concept is not limited to. the particular structure shown, but is capable of a variety of mechanical embodiments and is adaptable to any type of block molding machine employing a horizontally reciprocable feedpan. For example, it should be evident that the cut-off bar can be supported and given its desired movements by various meansother than those described and illustrated,

and that, if desired, the cut-off bar may comprise only part of the front end wall of the feed pan, or may even constitute an element additional to a fixed front wall. It will also be understood that the cut-0d bar may be so constructed as to omit. the detachable scraper shoes, and that its lower edge portion may be of any suitable construction depending upon the core and core bar arrangement ofthe mold box.

Similarly, the stripper shoe: wiperelement may take other forms, and: may be supported. by specifically different means, than those herein disclosed;

Various other changes, which will now suggest themselves to those skilled in the art, may be made in the form, details of construction and arrangement of. the parts without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a definition of. the limits of the invention.

What is claimed. is:

1. In. a machine; for molding masonry blocks, the combination of: an. open top mold box, a horizontally reciprccable feed pan open at the bottom for supplying moldable material to, said mold box through the open top of the latter, means carried by said feed pan for establishing the height of the mol'dable material left in said mold box by said pan, means mounted on and movable with the feed pan and operable while said pan is in motion for adjusting the position of said height establishing means to vary the height or" the moldable material in said mold box, and means located at a position remote from; said feed pan for controlling the operation of said adjusting means.

2. in a. machine for molding masonry blocks, the combination of. an open. topmold box, a. horizontally reciprocable feed. pan open at the bottom for supplying moldable material. to said mold box. through the open top of the latter, a vertically movable. member carried by said feed pan for establishing the height. of the moldable materialleft insaid mold box by said pan, means mounted on and movable with the feed pan. and operable while said pan is in motion for vertically adjusting; the position of said movable member to vary the height of the moldable material in said. mold. box, and means located at a position remote from said feed pan for controlling the operation of said adjusting means.

3.. In a machine for molding masonry blocks,

the combination of an open top mold. box, a horizontally reciprocable feed pan open. at the bottom. for supplying. mol'd'able material to said mold box through the open top of the latter, a

vertically movable member forming at least part of the. front. wall of, said feed pan adapted to control the height of the moldable material left pan to vary the height of the moldable material in said mold box, and means located at a position remote from feed pan for controlling the operation of said electrically actuated means.

4. In a block molding machine of the type including an open top mold box and a horizontally reciprooable, open bottom feed pan for supplying moldable material to said mold box through the open top of the latter, an improved feed pan comprising a pair of side walls, a transversely extending member forming at least part of the front wall of said feed pan and having a bottom edge portion adapted to scrape the upper surface of the moldable material supplied to said mold box by said pan and thereby establish the height of the moldable material left in said box, a pair of vertically movable elements carried by said side Walls adjacent the front ends thereof and so connected to said transversely extending member as to support the latter, and means mounted on and movable with the feed pan and operable while said pan is in motion for vertically adjusting the positions of saidelements relative to said side walls and thereby varying the height of the bottom edge portion of said transversely extending member, and means located at a position remote from said feed pan for controlling the operation of said adjusting means.

5. In a block molding machine of the type including an open top mold box and a horizontally reciprocable, open bottom feed pan for supplying moldable material to said mold box through the open top of the latter, an improved feed pan comprising a pair of side walls, a transversely extending member detachably connected to said side walls and forming at least part of the front wall of said feed pan, the bottom edge of said member being adapted to scrape the upper surface of the moldable material supplied to said mold box by said pan and thereby establish the height of the moldable material left in said box, and means mounted on and movable with said feed pan and operable while said pan is in motion, including an electric motor and a micrometrically movable transmission driven by said motor, for vertically adjusting the position of said member with respect to said side walls and thereby varying the height of the moldable material in said mold box, and a switch located at a position remote from said feed pan for controlling the operation of said electric motor.

6. In a block molding machine of the type including an open top mold box and a horizontally reciprocable, open bottom feed pan for supplying moldable material to said mold box through the open top of the latter, an improved feed pan comprising a pair of side walls, a transversely extending member forming at least part of the front wall of said feed pan and having a bottom edge portion adapted to scrape the upper surface of the moldable material supplied to said mold box by said pan and thereby establish the height of the moldable material left in said box, a pair of vertically movable elements carried by said side walls adjacent the front ends thereof and so connected to said transversely extending member as to support the latter, and means for vertically adjusting the positions of said elements relative to said side walls and thereby varying the height of the bottom edge portion of said transversely extending member, said means including a reversible electric motor mounted on and movable with the feed pan and operable while said pan is in motion, a pair of rods carried by and extending longitudinally of said side walls, means driven by said motor for moving said rods, and means for converting the movement of said rods into vertical movement of said elements.

'7. An improved feed pan for block molding machines as defined in claim 9 wherein each of said vertically movable elements comprises a plate slidable in a guide fixed to one of said side walls and 9, lug to which one end of said transversely extending member is connected, and which includes a pair of bell crank levers pivotally mounted on said side walls for connecting said rods to said plates.

8. In combination, a horizontally reciprocable feed pan for block molding machines comprising a pair of side walls, a transversely extending cut-off bar supported by said side walls and forming at least part of the front wall of the feed pan, and electrically actuated means carried by said side walls and operable while the feed pan is in motion for moving said cut-off bar upwardly and downwardly in a substantially vertical plane relative to said side walls, and a switch located at a position remote from said feed pan for controlling the operation of said electrically actuated means.

9. A horizontally reciprocable feed pan for block molding machines comprising a pair of side walls, a transversely extending cut-off bar forming the front wall of the feed pan, means for supporting the cut-off bar from said side walls including a pair of vertically adjustable elements carried by said side walls to which the end of said bar are connected, and means operable durin reciprocation of said feed pan for raising and lowering said elements relative to said side walls, whereby the height of said cut-off bar may be varied.

10. In combination, a horizontally reciprocable feed pan for block molding machines comprising a pair of side walls, a transversely extending cutoff bar forming the front wall of the feed pan, means for supporting said cut-off bar from said side walls including a pair of vertically adjustable elements carried by said side walls to which the ends of said bar are connected and electrically actuated means carried by said side walls and operable while the feed pan is in motion for raising and lowering said elements relative to said side walls, whereby the height of said cutoff bar may be varied, and a switch located at a position remote from said feed pan for controlling the operation of said electrically actuated means.

11. A horizontally reciprocable feed pan for block molding machines comprising a pair of side walls, a transversely extending cut-ofi bar forming the front wall of the feed pan, means for supporting said cut-oil bar from said side walls including a pair of guides fixed to said side walls and a mounting plate vertically slidable in each of said guides to which one end of said bar is connected, and means movable with said feed pan and operable during movement thereof for raising and lowering said mounting plates in said guides and thereby varying the vertical position of said cut-off 'bar.

12. A horizontally reciprocable feed pan for block molding machines comprising a pair of side walls, a transversely extending cut-off bar forming the front wall of the feed pan, means for supporting said cut-off bar from said side walls including a pair of guides fixed to said side walls and a mounting plate vertically slidable in each of said guides to which one end of said bar is connected, and means for raising and lowering said mounting plates in said guides and thereby vary- Number Name Date ing the vertical position of said cut-off bar, said 835,737 Simmons et a1 Nov. 13, 1906 means including a reversible electric -motor 876,388 Nieters Jan. 14, 1908 mounted on and movable with the feed pan, a 2,208,054 Reed July 16, 1940 pair of rods carried by and extending longitu- 5 2,242,690 Wallace May 20, 1941 dinally of said side walls, means driven by said 2,589,115 Nelson et a1 Mar. 11, 1952 motor for moving said rods, and connections be- FOREIGN PATENTS tweentsaid rods and'said mounting plates operable to convert the movement of the rods into Number Country Date vertical movement of the plates. 10 453,485 France 1913 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 289,397 Dietz Dec. 4, 1883 15 

